from chiplotle import *
from chiplotle.hpgl.commands import ER
from py.test import raises

def test_ER_01( ):
    '''ER cannot initialize with a scalar.'''
    assert raises(TypeError, 't = ER(1)')


def test_ER_02( ):
    '''ER cannot initialize with a list of length > 2.'''
    assert raises(ValueError, 't = ER([1, 2, 3, 4])')


def test_ER_03( ):
    '''ER can initialize with a list of length 2.'''
    t = ER([1, 2])
    assert t.xy == Coordinate(1, 2)
    assert t.format == 'ER1,2;'
